package com.ljc;

import java.util.Arrays;

/**
 * @author clj
 * @date 2022/9/27
 * @desc You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n,
 * representing the number of elements in nums1 and nums2 respectively.
 * <p>
 * Merge nums1 and nums2 into a single array sorted in non-decreasing order.
 * <p>
 * The final sorted array should not be returned by the function, but instead be stored inside the array nums1.
 * To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged,
 * and the last n elements are set to 0 and should be ignored. nums2 has a length of n.
 * <p>
 * Example 1:
 * Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
 * Output: [1,2,2,3,5,6]
 * Explanation: The arrays we are merging are [1,2,3] and [2,5,6].
 * The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.
 * <p>
 * Example 2:
 * Input: nums1 = [1], m = 1, nums2 = [], n = 0
 * Output: [1]
 * Explanation: The arrays we are merging are [1] and [].
 * The result of the merge is [1].
 * <p>
 * Example 3:
 * Input: nums1 = [0], m = 0, nums2 = [1], n = 1
 * Output: [1]
 * Explanation: The arrays we are merging are [] and [1].
 * The result of the merge is [1].
 * Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit
 */
public class E88MergeSortedArray {

    public static void main(String[] args) {
        int[] nums1 = new int[]{1, 2, 3, 0, 0, 0};
        int[] nums2 = new int[]{2, 3, 4};
        int m = 3, n = 3;
        int[] result = mergeSortedArray(nums1, m, nums2, n);
        System.out.println(Arrays.toString(result));
    }

    public static int[] mergeSortedArray(int[] nums1, int m, int[] nums2, int n) {
        for (int i = 0; i != n; ++i) {
            nums1[m + i] = nums2[i];
        }
        Arrays.sort(nums1);
        return nums1;
    }

    public static int[] mergeSortedArrayOld(int[] nums1, int m, int[] nums2, int n) {
        int p1 = m - 1, p2 = n - 1;
        int tail = m + n - 1;
        int cur;
        while (p1 >= 0 || p2 >= 0) {
            if (p1 == -1) {
                cur = nums2[p2--];
            } else if (p2 == -1) {
                cur = nums1[p1--];
            } else if (nums1[p1] > nums2[p2]) {
                cur = nums1[p1--];
            } else {
                cur = nums2[p2--];
            }
            nums1[tail--] = cur;
        }
        return nums1;
    }


}
